Chancery Causes are cases of equity. According to Black's Law Dictionary they are "administered according to fairness as contrasted with the strictly formulated rules of common law." A judge, not a jury, determines the outcome of the case; however, the judge is basing the decision on findings compiled and documented by Commissioners. Chancery causes are useful when researching local history, genealogical information, and land or estate divisions. They are a valuable source of local, state, social, and legal history and serve as a primary source for understanding a locality's history. Chancery causes document the lived experiences of free and enslaved individuals; women; children; people living with physical disabilities or mental health struggles; people living in poverty; defunct institutions and corporate entities; or those that may not have otherwise left traditional written histories.

Prince William County was named for William Augustus, duke of Cumberland and third son of King George II. It was formed from Stafford and King George Counties by a statute adopted in 1730. The county courthouse is in the city of Manassas, Virginia and the county administrative offices are in Woodbridge, Virginia.